* Revise reference implementation for ReduceL1 operation
* Revise reference implementation for ReduceL2 operation
* Move op_eval tests to backend unit tests
* Added minor changes
* Replace CoordinateTransform for CoordinateTransformBasic
* Added constant expression to set keep_dims as false
* Add const qualifier to local variables
* Use rank from host tensor to normalize axes
Gabriele Galiero Casay